This research proposal involves the study of trace elements in the brains of patients with Alzheimer's disease (presenile and senile dementia), aged individual with benign senile mental change, aged invididual without significant mental alterations and controls of a wide age spectrum from birth to late life. Material will be obtained primarily from autopsy specimens and rarely from brain biopsies. A broad spectrum of trace elements will be determined by highly sensitive instrumental and radiochemical neutron activation analysis. Correlative gross, histopathologic and selective electron microscopic studies will be performed on these brains. The overall goal of the study is to determine if elevated concentration or altered ratios of trace elements have an etiologic role in Alzheimer's disease and aging in the brain. This research is also aimed at defining normal levels of a broad spectrum of trace elements in brains of neurologically normal individuals of various ages. This study could possibly lead to therapeutic attempts in Alzheimer's disease and open further avenues of investigation to lead to a greater understanding of the aging process in the brain.